The present invention relates to lifting apparatus for lifting containers from a supporting surface on a lower level to a higher level via a vertical lift shaft. The invention is particularly useful in aircraft for storing galley articles within containers in the cargo hold and for retrieving such articles as and when desired. The invention is therefore described below with respect to such an application, but it will be appreciated that the invention could advantageously be used in many other applications.
The compact storing and retrieving of articles in general, and galley articles in particular, is a critical problem in aircraft design because of the need to maximize the utilization of space for passengers and/or cargo within the aircraft. My prior U.S. Pat. Nos. 6,059,229, 6,152,287 and 6,340,136 describe various arrangements for storing containers containing galley articles, such as wheeled carts and food trays, above the passenger compartment or below the passenger compartment, in a manner which permits such containers to be compactly stored, conveniently retrieved when desired, and then returned to their respective stored location. The present invention is particularly useful in such aircraft constructions wherein the containers containing the galley articles are stored in a cargo hold below the passenger compartment and are selectively lifted via a vertical lift shaft, installed in the main deck, into the passenger compartment. A plurality of the containers may thus be compactly supported on a supporting surface, e.g., in a standard size, in-flight container-holding system, and may be selectively shifted by a shifting mechanism to bring the container of a selected position on the supporting surface into precise alignment with the vertical lift shaft. The vertical lift shaft includes a lift member or platform which is movable upwardly to raise to the main deck a container selected to be retrieved, or downwardly to return the selected container to its respective position in the container-holding system in the cargo hold.
The possibility of misalignment of the lifting member, and/or the vertical lift shaft, with respect to the containers in the cargo hold is a serious problem in such aircraft during in-flight conditions because of the stress changes due to internal aircraft pressure variations. Such stress changes can produce misalignments between the containers in the cargo hold and the lift system, which can result in damage to, or even complete failure of, the container retrieving and returning system.
One object of the present invention is to provide lifting apparatus for lifting containers through a vertical lift shaft, which apparatus has a reduced sensitivity to misalignment of the containers with respect to the lift system and/or the vertical lift shaft. Another object of the invention is to provide a compact retrieving and returning apparatus for containers in aircraft which apparatus can accommodate, and compensate for, a relatively wide range of misalignments which may be caused by the in-flight or ground conditions of the aircraft.
According to one aspect of the present invention, there is provided lifting apparatus for lifting containers from a supporting surface on a lower level to a higher level via a vertical lift shaft, comprising: a lift member in the vertical lift shaft and movable upwardly and downwardly therethrough; a displaceable suspension member suspended from and below the lift member; the displaceable suspension member being displaceable in a horizontal direction with respect to the lift member, from a normal position in precise alignment with the vertical lift shaft, to a displaced position with respect to the lift member and vertical lift shaft; a spring loaded by the displacement of the displaceable suspension member when moved to its displaced position and urging, by the inherent elasticity of the spring the displaceable suspension to the normal position; and a guiding element carried by the displaceable suspension member; the guiding element having an inclined guiding surface effective, when engaged by a container during the downward movement of the lift member, to displace the displaceable suspension member in a horizontal direction with respect to the lift member and the vertical lift shaft, and thereby to load the spring; the arrangement being such that, when the lift member is lowered to engage a container on the supporting surface, the container engages the guiding surface of the guiding member to displace the displaceable suspension member horizontally and to load the spring; and when the container is lifted off the supporting surface during the upward movement of the lift member, the inherent elasticity of the spring returns the displaceable suspension member, and the container holder engaged thereby, to the normal position of the displaceable suspension member in alignment with the vertical lift shaft.
According to further features in the preferred embodiment of the invention described below, the displaceable suspension member carries a second guiding element having a second inclined surface located to be engaged by the container to be lifted, after traversing the first-mentioned guiding surface during the initial downward movement of the lift member.
According to still further features in the described preferred embodiment, the apparatus further comprises a drive for displacing the container in a second horizontal direction, orthogonal to the first horizontal direction, to effect the engagement of the container with the displaceable suspension member before the upward movement of the lift member for moving the container therewith through the vertical lift shaft. The engagement of the container with the displaceable suspension member before the upward movement of the lift member is effected by coupling elements carried by one receivable in coupling recesses in the other.
According to another aspect of the present invention, there is provided an aircraft comprising: a main deck dividing a section of the aircraft into a passenger compartment above the main deck, and a cargo hold below the main deck; a vertical lift shaft extending through the main deck into the cargo hold; a supporting surface in the cargo hold for supporting a plurality of containers in a plurality of positions; a shifting mechanism for shifting the plurality of containers to bring a container of a selected position on the supporting surface into precise alignment with the vertical lift shaft; a lift system including a lift member in the vertical lift shaft and movable upwardly and downwardly therethrough; a displaceable suspension member suspended from and below the lift member; the displaceable suspension member being displaceable in a horizontal direction with respect to the lift member, from a normal position in precise alignment with the vertical lift shaft, to a displaced position with respect to the lift member and vertical lift shaft; a spring loaded by the displacement of the displaceable suspension member when moved to its displaced position and urging, by the inherent elasticity of the spring the displaceable suspension to the normal position; and a guiding element carried by the displaceable suspension member; the guiding element having an inclined guiding surface effective, when engaged by one side of a container during the downward movement of the lift member, to displace the displaceable suspension member in a horizontal direction with respect to the lift member and the vertical lift shaft, and thereby to load the spring; the arrangement being such that, when the lift member is lowered to engage a container on the supporting surface, the container engages the guiding surface of the guiding member to displace the displaceable suspension member horizontally and to load the spring; and when the container is lifted off the supporting surface during the upward movement of the lift member, the inherent elasticity of the spring returns the displaceable suspension member, and the container engaged thereby, to the normal position of the displaceable suspension member in alignment with the vertical lift shaft.
According to yet another aspect of the present invention, there is provided a lift system comprising: a lift platform movable within a vertical lift shaft; a door movable from an open position to a closed position with respect to the vertical lift shaft; a door control system including a plurality of door sensors at different locations on the door for sensing the position of the door; a memory for storing a sequence of operation of the door sensors the door control system storing in the memory the sequence of operation of the door sensors during each door-closing operation; and a locking mechanism controlled by the door control system to lock the door closed, and to enable the lift system for operation only when the plurality of door sensors have been actuated according to the sequence of an immediately preceding door-closing operation as stored in the memory.
As will be described more particularly below, such container lifting apparatus can automatically accommodate a wide range of misalignments between the containers and the lift system vertical lift shaft. This makes the container lifting apparatus particularly useful for aircraft since it reduces the sensitivity of the system to misalignments in the aircraft structure caused by various stress conditions during in-flight operation of the aircraft. A further advantage is that the article lifting apparatus of the present invention is compatible with many different types of container storage, retrieval and returning systems, and generally requires little if any changes to accommodate different types of such systems.
Further features and advantages of the invention will be apparent from the description below.